It seemed somehow appropriate that Jimmy Montgomery's first day as Sunderland's special ambassador should end in a spot of FA Cup glory. It is 39 years since his double reflex save at Wembley ensured that Ian Porterfield's goal was sufficient to beat Leeds United and bring the trophy back to Wearside but, inspired by Martin O'Neill's dynamic management, Montgomery's old club have silverware in their sights once more.

Barring a Champions League miracle it looks as if Arsenal will not be winning anything again this season. Indeed it was perhaps not purely because of the plummeting February temperature that, at the end, Arsène Wenger partially covered his face with the protective, zipped-up collar of his managerial duvet coat.

As if listening to cheeky chants of "You're getting sacked in the morning" from jubilant Sunderland fans was not bad enough, Arsenal's manager had to endure the experience of seeing his disappointingly flat side deservedly lose to a team who, until O'Neill's transformative arrival, were dallying with relegation.

If O'Neill's central defensive partnership of John O'Shea and Michael Turner did an outstanding job of keeping Robin van Persie and company quiet, a counter-attacking Sunderland also impressed in possession.

Lee Cattermole proved arguably the evening's key figure in a holding central midfield role which took considerable pressure off his defence while James McClean's left-wing forays worried Arsenal.

A chill wind whipping off the river Wear proved so capricious that ball control assumed a whole new meaning. With the heavy pitch beginning to cut up the conditions were hardly ideal for a fast-tiring Arsenal side badly in need of restoring some morale-boosting fluency to their play following last Wedenesday's Champions League ignominy in Milan.

When Francis Coquelin, drafted in at left-back for the day, swiftly hobbled off with a hamstring injury it seemed that fortune was continuing to frown on Wenger's currently accident-prone defence.

With Sébastien Squillaci joining Johan Djourou in central defence, Thomas Vermaelen relocated to his less preferred left-back role where he frequently looked uneasy in the face of Sebastian Larsson, Sunderland's former Arsenal right-winger.

Across on the left, McClean regularly had the beating of Bacary Sagna and the young Irishman's runs and crosses at times provoked consternation among the visiting backline.

Although Stéphane Sessègnon was nominally deployed as Sunderland's lone striker Craig Gardner made frequent, defender-confounding late dashes into the penalty area from the heart of O'Neill's midfield quintet. With Cattermole, recovered from a hamstring strain, in such authoritative form Gardner was free to serve at times as a secondary counterattacking striker.

It was Djourou's foul on Gardner that precipitated the free-kick from which Sunderland took the lead. Larsson swung the ball in and Vermaelen's attempt at a headed clearance fell at the feet of Kieran Richardson.

O'Neill's left-back was unattended in acres of space but, even so, his handsome left-foot shot appeared poised to fly fractionally wide until it was deflected off Squillaci and into the bottom corner.

Wenger slumped deep into his padded seat in the away dugout. The row of stony-faced backroom staff lined up alongside a manager by now huddling into the protective folds of his coat as if it were a comfort blanket reflected an increasingly downbeat north London mood.

Visiting demeanours were hardly enhanced when Howard Webb refused Van Persie a penalty in the wake of a perceived foul from O'Shea after the Dutchman had collected Alex Song's clever reverse pass. Webb, though, adjudged that O'Shea had got the ball before bringing down Van Persie.

Earlier Gardner's challenge on Van Persie had earned a free-kick just outside the area, floated wide by Mikel Arteta, but Simon Mignolet's sole key save of the match involved him brilliantly tipping a shot from Gervinho, newly returned from the Africa Cup of Nations, to safety.

As the second half unravelled and the clock ticked remorselessly down, Wenger was forced into a double substitution. Squillaci, clutching a groin, and a limping Aaron Ramsey trudged off, heads bowed, and were replaced by Tomas Rosicky and Theo Walcott.

Some of Van Persie's off-the-ball attacking movement was superb but the service he received proved less so and during an odd pause in play the striker's body language suggested he was a little fed up.

It was time for some of the much-vaunted leadership hitherto conspicuous by its absence and Van Persie duly decided to try galvanising his colleagues. When Arteta indicated he would be taking a free-kick, Arsenal's captain overruled him taking the set play himself and, in a cameo emblematic of Wenger's woes, saw it deflected wide.

Luck similarly deserted Alex Oxlade-Chamberlain when, attempting to help out defensively, he merely succeeded in inadvertently nudging the ball into his own net.

Sunderland's second goal began with Arteta's slip which permitted Sessèngon to race almost halfway down the pitch before slipping a pass to Larsson. Although the Swede's shot rebounded off a post, the back-tracking Oxlade-Chamberlain proved powerless to prevent the ball entering the net.

It proved the cue for the finally confident home supporters to break into one of their favourite ditties. "Are you watching," they sang. "Are you watching Newcastle?"